Anet A8 5 Button to Encoder Button change

Update 30-SEP-2018
11MASTER started the following thread that you may find helpful regarding using the more recent Marlin version rather than the ancient SkyNet Marlin port.:
https://reprap.org/forum/read.php?415,833120,833120#msg-833120

Update 27-MAY-2017
Added the SkyNet 2.3.1 headers and sources I modified. Note that these sources include auto leveling 3DTouch changes. Again, please note that these are SkyNet 2.3.1 changes.
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There’s probably many other ways to convert from the 5 button display to an encoder button, but most of the conversions I’ve seen ended up with the original display location unused and the display sitting in a printed mount (to quote Sienfeld; "Not that there’s anything wrong with that.") My primary motivation is to free up pins on the Mega1284P. I’m currently using an SN04 proximity sensor for auto leveling, and it’s working fine for printing PLA on blue painters tape, but I’d like to move to printing ABS on glass, and to do t